The dynamic Casimir effect is a possible mechanism for propulsion. Previous investigations assumed mechanical motion of a mirror to generate thrust. Because of the finite strength of materials and the high frequencies necessary, the amplitudes of motion must be restricted to the nanometer range.
More than 60 years ago, H. B. G. Casimir and Casimir and D. Polder explained the retarded van der Waals force in terms of the zero-point energy of a quantized field. Both the static and dynamic Casimir effects are discussed in several large reviews. The dynamic Casimir effect has involved the interaction between moving mirrors and the ground state (“vacuum state’) of the electromagnetic field.
When estimating the magnitude of the force that could be generated, Maclay and Forward assumed that the amplitude of high frequency motion of an actual mirror need be in the nanometer range due to the finite strength of materials. This restriction limits the possible propulsive force to very small values.
In a thorough treatment of the pressure on moving mirrors due to the Casimir effect, Neto and his colleagues took a perturbative approach consistent with the assumption that the mirror motion be constrained to very small amplitudes.